Anticancer platinum complexes are known as one of anticancer agents, and cisplatin (chemical name: cis-diamminedichloridoplatinum(II)) was developed as the first anticancer platinum complex. However, there is a problem with cisplatin in that it has many side effects, such as nephrotoxicity, haematotoxicity, gastrointestinal toxicity and neurotoxicity. Then, carboplatin (chemical name: cis-diammine(1,1-cyclobutanedicarboxylato)platinum(II)) was next developed to reduce the nephrotoxicity of cisplatin and to increase its water solubility, but it does not necessarily have a satisfactory anticancer activity. Then, oxaliplatin (chemical name: oxalato(1R,2R-1,2-cyclohexanediamine)platinum(II)) was developed as the third generation of anticancer platinum complexes (the patent literature 1). Oxaliplatin has an anticancer activity even against cisplatin-resistant cancer cells and little toxicity such as nephrotoxicity and haematotoxicity, and therefore excels among others, but there is still room for improvement in respect of the anticancer activity.
Meanwhile, the intracellular target molecule of the aforementioned platinum complexes is DNA, and the platinum complexes are considered to exhibit an anticancer activity by forming cross-links with a constituent base of DNA. Examples of the cross-link formations include DNA-protein cross-links, DNA intrastrand cross-links and DNA interstrand cross-links. Cisplatin, for example, is considered to form DNA intrastrand cross-links and/or DNA interstrand cross-links.
DNA has a helical structure, which is a chiral structure. For this reason, when the platinum complexes bind to DNA, their chirality is anticipated to greatly affect their own anticancer activity, but at present, it is not clear how the chirality affects the anticancer activity.
Patent Literature 1: JP-A 6-211883